The case,PSU and DVD-RW would be brand new for this build. My case is a full atx not many people want. I can upgrade to 16GB of RAM if they want and I can upgrade the 5850 to an ASUS DCU2 GTX680 4GB if they really want for an extra $350.

I'm not really planning on it. I love the 680. I can finally run GTAIV fully modded with maxed out settings and ENB shaders smoothly. Same with Fallout 3 (why I wanted a 4GB card). It absolutely kills BF3 and everything I've thrown at it. I'm trying to order a bracket to install my second H100 onto it. I hit 9500 in 3dMark 11 with my 1100T at 4.2 and I'm curious if I can touch 10K with the H100 on both the CPU and GPU. I'm not like these other idiots on here that all buy these high end cards and processors with aftermarket coolers and swear up and down they've never overclocked anything. For the record I run the 1100T at 3.8 daily on a 990FX Sabertooth board.

I'd prefer to keep it but I thought the system might not sell with a 5850 which is why I'd want an extra $350 for the 680. This is my second computer. I'm a contract employee whose contract expires at the end of July so I'm just looking to liquidate a few things around the house.

I think you're a little high on those numbers. You can try it out, but I don't think you'll sell an 100T system for $920 with a 5850, or $1270 with a 680. You might be able to get those numbers if you part out (but not on the SSD or the Green), but not as a complete system, methinks.